diff --git a/Signal/src/UserInterface/Notifications/UserNotificationsAdaptee.swift b/Signal/src/UserInterface/Notifications/UserNotificationsAdaptee.swift
index 361859e09..0c5e5877e 100644
--- a/Signal/src/UserInterface/Notifications/UserNotificationsAdaptee.swift
+++ b/Signal/src/UserInterface/Notifications/UserNotificationsAdaptee.swift
@@ -283,11 +283,6 @@ extension OWSSound {
             owsFailDebug("filename was unexpectedly nil")
             return UNNotificationSound.default
         }
-        return UNNotificationSound(named: convertToUNNotificationSoundName(filename))
+        return UNNotificationSound(named: UNNotificationSoundName(rawValue: filename))
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertToUNNotificationSoundName(_ input: String) -> UNNotificationSoundName {
-	return UNNotificationSoundName(rawValue: input)
-}
diff --git a/Signal/src/ViewControllers/Call/CallViewController.swift b/Signal/src/ViewControllers/Call/CallViewController.swift
index 779ba56f3..7d5837a9c 100644
--- a/Signal/src/ViewControllers/Call/CallViewController.swift
+++ b/Signal/src/ViewControllers/Call/CallViewController.swift
@@ -124,7 +124,7 @@ class CallViewController: OWSViewController, CallObserver, CallServiceObserver,
                     }
 
                     // Don't use receiver when video is enabled. Only bluetooth or speaker
-                    return convertFromAVAudioSessionPort(portDescription.portType) != convertFromAVAudioSessionPort(AVAudioSession.Port.builtInMic)
+                    return portDescription.portType != AVAudioSession.Port.builtInMic
                 }
             }
             return Set(appropriateForVideo)
@@ -1225,8 +1225,3 @@ extension CallViewController: CallVideoHintViewDelegate {
         updateRemoteVideoLayout()
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertFromAVAudioSessionPort(_ input: AVAudioSession.Port) -> String {
-	return input.rawValue
-}
diff --git a/Signal/src/ViewControllers/MediaPageViewController.swift b/Signal/src/ViewControllers/MediaPageViewController.swift
index 5ff4fd936..68f1abf2d 100644
--- a/Signal/src/ViewControllers/MediaPageViewController.swift
+++ b/Signal/src/ViewControllers/MediaPageViewController.swift
@@ -75,9 +75,10 @@ class MediaPageViewController: UIPageViewController, UIPageViewControllerDataSou
 
         let kSpacingBetweenItems: CGFloat = 20
 
+        let options: [UIPageViewController.OptionsKey: Any] = [.interPageSpacing: kSpacingBetweenItems]
         super.init(transitionStyle: .scroll,
                    navigationOrientation: .horizontal,
-                   options: convertToOptionalUIPageViewControllerOptionsKeyDictionary([convertFromUIPageViewControllerOptionsKey(UIPageViewController.OptionsKey.interPageSpacing): kSpacingBetweenItems]))
+                   options: options)
 
         self.dataSource = self
         self.delegate = self
@@ -829,14 +830,3 @@ extension MediaPageViewController: CaptionContainerViewDelegate {
         captionContainerView.isHidden = true
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertToOptionalUIPageViewControllerOptionsKeyDictionary(_ input: [String: Any]?) -> [UIPageViewController.OptionsKey: Any]? {
-	guard let input = input else { return nil }
-	return Dictionary(uniqueKeysWithValues: input.map { key, value in (UIPageViewController.OptionsKey(rawValue: key), value)})
-}
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertFromUIPageViewControllerOptionsKey(_ input: UIPageViewController.OptionsKey) -> String {
-	return input.rawValue
-}
diff --git a/Signal/src/views/MarqueeLabel.swift b/Signal/src/views/MarqueeLabel.swift
index 26b31a9d7..c505510bf 100644
--- a/Signal/src/views/MarqueeLabel.swift
+++ b/Signal/src/views/MarqueeLabel.swift
@@ -1089,20 +1089,19 @@ open class MarqueeLabel: UILabel, CAAnimationDelegate {
     }
 
     private func timingFunctionForAnimationCurve(_ curve: UIView.AnimationCurve) -> CAMediaTimingFunction {
-        let timingFunction: String?
-
+        let timingFunction: CAMediaTimingFunctionName
         switch curve {
         case .easeIn:
-            timingFunction = convertFromCAMediaTimingFunctionName(CAMediaTimingFunctionName.easeIn)
+            timingFunction = .easeIn
         case .easeInOut:
-            timingFunction = convertFromCAMediaTimingFunctionName(CAMediaTimingFunctionName.easeInEaseOut)
+            timingFunction = .easeInEaseOut
         case .easeOut:
-            timingFunction = convertFromCAMediaTimingFunctionName(CAMediaTimingFunctionName.easeOut)
+            timingFunction = .easeOut
         default:
-            timingFunction = convertFromCAMediaTimingFunctionName(CAMediaTimingFunctionName.linear)
+            timingFunction = .linear
         }
 
-        return CAMediaTimingFunction(name: convertToCAMediaTimingFunctionName(timingFunction!))
+        return CAMediaTimingFunction(name: timingFunction)
     }
 
     private func transactionDurationType(_ labelType: MarqueeType, interval: CGFloat, delay: CGFloat) -> TimeInterval {
@@ -1840,13 +1839,3 @@ fileprivate extension CAMediaTimingFunction {
         return pointArray
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertFromCAMediaTimingFunctionName(_ input: CAMediaTimingFunctionName) -> String {
-	return input.rawValue
-}
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertToCAMediaTimingFunctionName(_ input: String) -> CAMediaTimingFunctionName {
-	return CAMediaTimingFunctionName(rawValue: input)
-}
diff --git a/SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift b/SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift
index d9c6fbb02..9480f2ecf 100644
--- a/SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift
+++ b/SignalMessaging/ViewControllers/AttachmentApproval/AttachmentApprovalViewController.swift
@@ -65,9 +65,11 @@ public class AttachmentApprovalViewController: UIPageViewController, UIPageViewC
         self.mode = mode
         let attachmentItems = attachments.map { SignalAttachmentItem(attachment: $0 )}
         self.attachmentItemCollection = AttachmentItemCollection(attachmentItems: attachmentItems)
+
+        let options: [UIPageViewController.OptionsKey: Any] = [.interPageSpacing: kSpacingBetweenItems]
         super.init(transitionStyle: .scroll,
                    navigationOrientation: .horizontal,
-                   options: convertToOptionalUIPageViewControllerOptionsKeyDictionary([convertFromUIPageViewControllerOptionsKey(UIPageViewController.OptionsKey.interPageSpacing): kSpacingBetweenItems]))
+                   options: options)
         self.dataSource = self
         self.delegate = self
 
@@ -792,14 +794,3 @@ extension AttachmentApprovalViewController: AttachmentApprovalInputAccessoryView
         isEditingCaptions = false
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertToOptionalUIPageViewControllerOptionsKeyDictionary(_ input: [String: Any]?) -> [UIPageViewController.OptionsKey: Any]? {
-	guard let input = input else { return nil }
-	return Dictionary(uniqueKeysWithValues: input.map { key, value in (UIPageViewController.OptionsKey(rawValue: key), value)})
-}
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertFromUIPageViewControllerOptionsKey(_ input: UIPageViewController.OptionsKey) -> String {
-	return input.rawValue
-}
diff --git a/SignalMessaging/environment/OWSAudioSession.swift b/SignalMessaging/environment/OWSAudioSession.swift
index ae0e11c17..057ff15f5 100644
--- a/SignalMessaging/environment/OWSAudioSession.swift
+++ b/SignalMessaging/environment/OWSAudioSession.swift
@@ -106,19 +106,19 @@ public class OWSAudioSession: NSObject {
             // session handling.
         } else if aggregateBehaviors.contains(.playAndRecord) {
             assert(avAudioSession.recordPermission == .granted)
-            try avAudioSession.setCategory(AVAudioSession.Category(rawValue: convertFromAVAudioSessionCategory(AVAudioSession.Category.record)))
+            try avAudioSession.setCategory(.record)
         } else if aggregateBehaviors.contains(.audioMessagePlayback) {
             if self.device.proximityState {
                 Logger.debug("proximityState: true")
 
-                try avAudioSession.setCategory(AVAudioSession.Category(rawValue: convertFromAVAudioSessionCategory(AVAudioSession.Category.playAndRecord)))
+                try avAudioSession.setCategory(.playAndRecord)
                 try avAudioSession.overrideOutputAudioPort(.none)
             } else {
                 Logger.debug("proximityState: false")
-                try avAudioSession.setCategory(AVAudioSession.Category(rawValue: convertFromAVAudioSessionCategory(AVAudioSession.Category.playback)))
+                try avAudioSession.setCategory(.playback)
             }
         } else if aggregateBehaviors.contains(.playback) {
-            try avAudioSession.setCategory(AVAudioSession.Category(rawValue: convertFromAVAudioSessionCategory(AVAudioSession.Category.playback)))
+            try avAudioSession.setCategory(.playback)
         } else {
             ensureAudioSessionActivationStateAfterDelay()
         }
@@ -215,8 +215,3 @@ public class OWSAudioSession: NSObject {
         }
     }
 }
-
-// Helper function inserted by Swift 4.2 migrator.
-private func convertFromAVAudioSessionCategory(_ input: AVAudioSession.Category) -> String {
-	return input.rawValue
-}